Masamha Exam 3 Materials Flashcards
anti-protozoals
What are some general considerations when using anti-protozoal drugs?
- many not safe for use in pregnancy
- considered toxic at therapeutic doses, so serious side effects may occur especially on cells with high metabolic rate
- drug resistance
- some drugs can only be obtained directly from the CDC
anti-protozoals
What is the amebiasis species that causes disease in humans?
Entamoeba histolytica
anti-protozoals
How are amebiasis transmitted?
oral-fecal route
anti-protozoals
How do amebiasis infect humans?
- an amebic cyst survives the gastic acid contents
- passes into lumen of intestine
- transforms into trophozoites which reside in the large intestine
anti-protozoals
What are the symptoms of an Entamoeba histolytic infection?
- asymptomatic if in the intestinal lumen
- servere diarrhea and abdominal cramps when trophozoites invade the intestinal lumen
- amebic colitis and bloody diarrhea (AMEBIC DYSENTERY) when trophozoites ulcerate colonic mucosa
- liver abscess when trophozoites infect portal vein
anti-protozoals
What is the treatment for asymptomatic intestinal lumen amebiasis infection?
- paromomycin
- iodoquinol
eliminate cysts in bowel lumen, used in addition to other drugs to treat other forms of amebiasis
anti-protozoals
What is the contraindication to Iodoquinol?
reaction to iodine
anti-protozoals
What is the use of nitroimidazoles?
mild-moderate infection and invasive colitis (intestinal, extraintestinal, and tissue infection) and dysentry- kills trophozoites in bowel wall and liver
not effective at targeting cysts in bowel lumen
anti-protozoals
What drugs are nitroimidazoles?
- metronidazole
- tinidazole
- nitazoxanide
anti-protozoals
What is the mechanism of action of metronidazole?
ferredoxin is reduced via PYRUVATE-FERREDOXIN OXIDOREDUCTASE (PFOR) enzyme which activates metronidazole = cytotoxic nitro free radical that can bind DNA and protein which inhibits DNA synthesis and induce DNA degradation= cell death
anti-protozoals
What is the mechanism of action of tinidazole?
creates cytotoxic free radicals and drug interactions
anti-protozoals
What is the mechanism of action of nitazoxanide?
differs from other nitroimidazoles, noncompetitive inhibition of pyruvate ferredoxin oxidoreductase (PFOR) which is essential for anaerobic energy metabolism
anti-protozoals
What is cryptosporidiosis?
waterborne disease caused by cryptosporidium spp. which presents with watery diarrhea (dehydration), cramps, N/V, fever
life threatening to immunocompromised pt
anti-protozoals
What is the treatment for Cryptosporidiosis?
nitazoxanide
anti-protozoals
What is Giardiasis?
intestinal parasite (giardia lamblia-a flagellate) which presents with diarrhea, abdominal cramps, greasy stools that float, dehydration, in severe cases: weight loss, malnutrition in kids due to failure to absorb fat
anti-protozoals
What is the treatment for giardiasis?
any nitroimidazole but metronidazole is 1st line
anti-protozoals
What is trichomoniasis?
STD, common cause of vaginitis and urethritis which presents with itching/irritation, dicomfort, and discharge
anti-protozoals
What is the treatment for trichomoniasis?
any nitroimidazole, but metronidazole is first line
anti-protozoals
How is toxoplasmosis transmitted?
foodborne- undercooked or contaminated meats and vegetables, animals (cats), and fetal transmission
anti-protozoals
What is the presentation of toxoplasmosis?
most healthy people are asymptomatic, but may cause mild flu like illness in healthy individuals
in immunocompromised and pregnant pts it can cause severe illness and miscarriage/stillbirth of unborn children
anti-protozoals
What is the treatment for toxoplasmosis?
pyrimethamine AND sulfadiazine (for synergistic effects) AND leucovorin calcium (due to induced folate deficiency from pyrimethamine)
anti-protozoals
What is the cause of african sleeping sickness?
tsetefly transmits Tb gambiense or Tb rhodesiense
anti-protozoals
What is the use of pentamidine isethionate?
early stages of african sleeping sickness caused by Tb gambiense (no CNS involvement)
anti-protozoals
What is the mechanism of action of Pentamidine isethionate?
targets and binds DNA in kinetoplase to inhibit replication and function
anti-protozoals
What drugs treat african sleeping sickness?
- pentamidine isethionate
- suramin
- eflornithine
- melarsoprol
anti-protozoals
What drug for the treatment of african sleeping sickness has a 4-6% death rate of users?
melarsoprol
for late stage with CNS involvement (high mortality)
anti-protozoals
What is the indication of Suramin?
early stage african sleeping sickness
anti-protozoals
What is the indication of eflornithine?
early or late (CNS involvement) african sleeping sickness
anti-protozoals
What are adverse effects of suramin?
neurologic effects
anti-protozoals
What are the adverse effects of eflornithine?
death (1%)
anti-protozoals
What is the mechanism of action of melarsoprol?
inhibits pyruvate kinase= inhibits glycolysis= decrease ATP synthesis which is essential to the survival of the organism
anti-protozoals
What is the cause of Chaga’s disease?
trypanosoma cruzi
anti-protozoals
What is the treatment for chaga’s disease?
- benznidazole
- nifurtimox
anti-protozoals
What are the monitoring parameters for patients on treatment for chaga’s disease?
- blood count
- hepatic function panel
- CMP
anti-protozoals
What is the mechanism of action of benznidazole?
inhibit protein and RNA synthesis
anti-protozoals
What is the mechanism of action nifurtimox?
generates intracellular oxygen radicals
CDC only
anti-helmintics
What is mazzotti reaction?
immunologic reaction (toxicity) due to dead and dying worms- can be life threatening
anti-helmintics
What is the mechanism of action of praziquantel?
increase the cell wall permability to Ca2+ (increased cellular Ca2+)= paralysis of worm/detachment= expulsion
anti-helmintics
What is the indication of praziquantel?
- cestodes
- trematodes
anti-helmintics
What antihelmintics do not cause mazzotti reaction?
- praziquantel
- pyrantel pamoate
- benzimidazoles
anti-helmintics
What parasites is pyrantel pamoate the drug of choice for?
- pinworms (enterobius vermicularis)
- hookworms
anti-helmintics
What is the mechanism of action of pyrantel pamoate?
nicotinic receptor agonist= paralysis= expulsion
anti-helmintics
What drug can be used for mixed parasitic infections?
benzimidazoles (albendazole, mebendazole, not triclabendazole)
anti-helmintics
What antihelmintic drugs are contraindicated in pregnancy?
- benzimidazoles (albendazole, mebendazole, triclabenazole)
- ivermectin (safety not estabilished)
anti-helmintics
What is th mechanism of Ivermectin?
GABA agonist= Cl- influx= paralysis= death
mazzotti reaction
anti-helmintics
What is the indication of ivermectin?
nematode infections including onchocerciasis (african river blindness)
anti-helmintics
In what pt populations should ivermectin not be used?
- pregnent pt
- pt with meningitis
anti-helmintics
What is the use of Diethylcarbamazine?
worms that effect the lymph nodes
CDC only
anti-helmintics
What is the use of moxidectin?
onchocerciasis (african river blindness) that is resistant to ivermectin
ectoparasites
What is the 1st line treatment option for lice/scabies?
permethrin
ectoparasites
What is the use of pyrethrins?
lice only
ectoparasites
What drug can only be used to treat scabies?
crotamiton
ectoparasites
What is the treatment for head lice only?
- spinosad
- malathion
- pyrethrins
